Percussive tool.



G.' J. GAWLEY.

PERCUSSWE TOOL.

APPLICATION'HLED APR.24, 1916.

1,225,612. Patented May 8,1917.

G. J. GAWLEY..

PERCUSSIVE TOOL.

APPLICATION FILED APR.24. 191s.

Patented May 8, 1917.

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GEORGE JAMES GAWLEY, 0F FLEET, ENGLAND.

PERCUSSIVE TOOL.

1,2,25 61,12; Specification of Letters Patent.

Application filed. April 24, 1916.

To all whom it may concern:

Be it known that I, Gnoncn JAMns GAw 1.121, a subject of the King of Great Britain, residing at Kent House, Fleet, Hampshire, England, have invented new and useful Improvements in Percussive Tools, of which the following is a specification.

My invention relates to means whereby atmospheric pressure may be used as the motive force in delivering percussive blows such as is necessary in using chisels, calking tools, percussive drills, hammers and the like.

The means which I employ for the purposes of my invention comprise a piston sliding in a cylinder or chamber, completely closed at one end in such a manner that admission of air, on one side of the piston, is impossible, whereby the relative movement of the said piston and cylinder in one direction will tend to create a vacuum, while the return movement will be effected by the atmospheric pressure.

My invention will be readily understood by reference to the accompanying drawings, in which Figure 1 represents in sectional elevation the simplest application of my invention.

Fig. 2 is a longitudinal section illustrating a modification of the invention.

Fig. 3 is a section on the line 33, Fig. 2, but drawn to a larger scale than the said figure, and

Fig. 4 is a view drawn to the same scale as Fig. 2 but showing the parts in a differ ent position.

In the arrangement shown in Fig. l, a indicates the cylinder, which is completely closed at the end Z) and which for convenience I will refer to as the head of the cylinder, the said head being shaped so that it can be, for instance, placed in contact *ith the object to be driven, say, for instance, a nail or have formed in it a socket as indicated by the dotted lines o intowhich a chisel, calking tool, or other instrument can be introduced.

0 is a piston sliding within the cylinder a and secured to a rod (Z, the end of which latter projects through the rear end of the cylinder and is provided with a knob or handle so that it can be readily grasped to withdraw the said piston and create a vacuum between the same and the head Z).

It will be understood that when the piston c has been so drawn out and is released that Patented May 8, 1%17.

Serial No. 93,291.

the air which enters behind the piston will act upon the latter and drive it forward so that it will impinge upon or against the head 7) with a momentum corresponding with the weight of the piston and rod and the velocity.

In the apparatus illustrated in Figs. 2 to 4c the piston, instead of being pulled outward to produce the vacuum, is held stationary, the cylinder being moved relatively thereto. This apparatus comprises an outer cylinder 0 closed at one end by a disk f and having at the other end an anvil 9 upon which the blows of the tool are delivered, the said anvil being, as shown, formed with a collar it between which and a collar 71 of the cylinder 6 a spring j is placed. Within the cylinder 6 is arranged the vacuum cylinder 7; the ends of: which are closed by disks Z, Z while within the said cylinder is arranged a vacuum piston m. The said vacuum cylinder 6 is connected by rods 72, n with a handle 0 which in turn is fixed to a cylinder p which telescopes upon the cylinder 6, sutlicient space being left between the said cylinders 72 and c to allow of the introduction of a spiral spring 9. The vacuum piston m has attached to it a hammer face 1" and has also connected to it a rod 8 which slides through the disk Z of the cylinder is; the outer end of the said rod 3 is notched at a, as shown in Fig. 3 and has arranged in conjunction with it spring pawls 24 designed to be separated by the wedge 1) upon the handle 0 when the latter reaches the limit of its inward movement.

The operation of the apparatus is as follows Assume the parts to be in the position shown in Fig. 52, which is the normal position of the apparatus when not in use, the operator now takes the apparatus in his hands and pushes in the outer cylinder 7) against the pressure of the spring 9 with the result that the inner cylinder 70, which is connected with the cylinder 29 by the rods a, n is pushed inward so that its end Z is moved away from the piston m to the position shown in Fig. t, a vacuum being thereby formed between them.

As the cap or handle 0 reaches the extremity of its inward movement, the wedge 11 comes into operative connection with the pawls u and separates them so that the head of the piston rod 8 is disengaged from the said pawls with the result that, under the at c is released the latter is returned from the position shown in Fig. 4: to that shown in Fig. 2 under the action of the spring 9 when the operation hereinbefore described can be repeated.

The apparatus shown in Figs. 2 to 4 is primarily designed for driving nails, for which purpose the cylinder 6 has at the striking end a yielding spring foot to applied to it, the said foot being formed with aseries of slots :or openings to facilitate the adjustment of the tool. It will be understood, however, that a holder might be provided for a chisel or other tool.

Claims: I

1. An apparatus for utilizing atmospheric pressure for delivering impacts comprising a chamber having a closed end adapted .to be placed against the article ,to be struck, the opposite end of said chamber being open to the atmosphere, a piston mounted in said chamber and adapted to be moved toward said closed end tor delivering an impact thereto by atmospheric air entering said cylinder and means for moving said piston away from the closed end of the cylinder,

whereby a vacuum will be created between the closed end of the cylinder and said piston.

2. An apparatus for utilizing atmospheric pressure for delivering impacts comprising a cylinder having an anvil at one end, a second cylinder slidably mounted in the first named cylinder, and provided with a closed end which is adapted to contact with said anvil, said second cylinder being open to the atmosphere at its opposite end, a piston slidably mounted in the second cylinder and adapted to be moved away from the closed end to create a vacuum between the piston and the closed end of the second cylinder, and means for moving the second cylinder relatively to the piston whereby a vacuum will be created in the second cylinder on one side of the piston and atmospheric air will act on the opposite side of the piston.

Apparatus for utilizing atmospheric pressure for operating percussive tools, comprising a cylinder or chamber, closed at one end, an outer cylinder in which it slides, a piston sliding within the inner cylinder, a handle or extension connected to the said inner cylinder, a guard or shield on the said handle which telescopes over the outer cylinder, means for connecting the piston with the outer cylinder and a device in connection with the handle or extension tor disconnecting the piston from the outer cylinder so that the said piston can move under atmospheric pressure to strike the base of the inner cylinder, substantially as hereinbefore described.

4. An apparatus for utilizing atmospheric pressure tor delivering an impact comprising .a chamber having a closed end adapted 'to be placed in contact with the surface to be struck, the opposite end of the chamber being open to the atmosphere, a member slidably mounted in said chamber, and

means for moving said member away from the closed end of said chamber to create a vacuum in said chamber between the closed end and member, said member being moved toward said closed end by atmospheric air entering the open end of the chamber.

5. An apparatus for utilizing atmospheric pressure for delivering an impact, comprising a cylinder closed at one end, an outer cylinder in which the first cylinder slides, a piston. slidably mounted in the inner cylinder, means for moving the inner cylinder relative to the piston for creating a vacuum between the piston and the closed end of the inner cylinder, means for detachably connecting the piston with the outer cylinder, and means for disconnecting the outer cylinder and piston so that the said piston can move under atmospheric pressure to strike the base-of the inner cylinder.

GEORGE JAMES GAVVLEY.

WVitnesses:

C. G. BEDFERN, JOHN E. BOUSFIELD.

Copies of this patent may be obtained for five cents each, by addressing the pcon missioner ,of Patents, Washington, J15. 

